Barrel safety latch



May 15, 1962 B. DARslE 3,034,407

BARREL SAFETY LATCH da. g 8 ,MW/4% 2 Sheets-Sheet 2 B. DARSIE BARREL SAFETY LATCH May l5, 1962 Filed April 20, 1961 IN VEN TOR :Enum-l s :nri E.

3,934,407 Patented May 15, 1962 ice 3,034,467 BARREL SAFETY LATCH Burns Dai-sie, Rockford, lll., assignor to the United States f America as represented by the Secretary of the rmy Fata Apr. zo, 1961, ser. No. io4,4s9 1i claims. (ci. :t9- 14) This invention relates to an automatic gun provided with a quick change barrel and is more particularly directed to means for releasably latching the barrel in the fully assembled position so that the gun can be tired only if the latch is in proper engagement with the barrel.

It is one object of this invention to provide for those automatic guns, in which the barrel is adapted for quick replacement and is releasahly locked in positionby latch means, a safety device actuable thereby so as to stop or prevent discharge of the gun when the barrel is not fully locked.

It is another object of this invention to provide such a latch-actuated safety device for automatic guns which iire from an open bolt position so that, if the gun trigger is accidentally actuated during replacement of a barrel, the sear will not be actuated to release the bolt to the battery position and, therefore, require that the gun be recharged before it is ready to be tired, whereby loss of valuable time, in what might be a critical situation, is prevented.

It is a further object of this invention to provide such a latch-actuated safety device so as to cooperate with a cam device provided in the trigger mechanism for converting pivotal displacement of a trigger to longitudinal displacement of a Sear-actuated trigger bar, whereby, the cam device is made inoperative when the latch is not fully displaced to lock the barrel in place and when the barrel is removed from the gun.

lt is a further object of this invention to provide such a latch-actuated safety device which is simple but rugged in construction, easy to manufacture, and positive in operation.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

FIG. l is a longitudinally cross-sectioned, fragmentary view of an automatic gun showing in one fragment the sear holding the bolt in the recoil position and in a for ward section the `barrel locked in the assembled position;

FIG. 2 is a view taken along line 2--2 of FIG. l;

FiG. 3 is a view taken along line 3-3 of FIG. 1;

FIG. 4 is a side, elevational view of the fragments shown in FIG. l and partially cross-sectioned;

FiG. 5 is a View taken along line 5-5 of FIG. 3;

FIG. 6 is a view taken along the same line as FIG. 3 but showing the relationship of the parts with the barrel removed; and

FIG. 7 is a view taken along line 7-7 of FIG. 6.

Shown in the figures is a recoil-operated automatic gun 12 having a receiver 14 in which a bolt 16 is disposed for axial reciprocation between a battery and a recoil position. A barrel jacket 18 is iixedly mounted on the front end of receiver 14 so as to extend forwardly therefrom. Barrel jacket 18 slidingly receives a barrel assembly '2d which includes a barrel 22 and a breech ring 24 secured in receiver 14 for limited longitudinal reciprocation. Barrel 22 is provided with a chamfer 25 around the outside edge of the breech end and with locking threads 2o formed forwardly thereof, which locking threads are interrupted by three, symmetrically spaced, longitudinal recesses 28 to permit passage therethrough of mating interrupted threads 30 formed inside of breech ring 24 at the rear end thereof. Full engagement is made between locking threads 26 and interrupted threads 30 when barrel 22 is inserted into breech ring 24 to where the segments of locking threads 26 are positioned for .engagement with interrupted threads Sil and thenv rotated approximately 60. Each of the recesses 28 is provided at the front end with a radial ramp 31 which blends outwardly to the periphery of barrel 22. Y

Provided on the top of barrel jacket 18 and adjacent the rear end thereof is a yoke 32 which supports a pin 33v disposed laterally therethrough. Pin 33 pivotally mounts a lever 34 kof inverted, U-coniguration so that a front portion of the lever, noted at 36, extends forwardly from the pin and a thumb portion 38 extends rearwardly therefrom. Pin 33 is spaced from the outside of barrel jacket 18 to provide suiiicient clearance between the barrel'jacket and lever 34 for pivotal displacement thereof. Extending laterally through the depending sides of lever 34 at front portion 36 is a pin 4d which extends transversely through the top of a cylindrical key 42. Key 42 extends downwardly through a mating bore 44 in lbarrel jacket 18 and a longitudinal slot 46 in breech ring 24 so that the free end of the key is receivable by a longitudinal channel 48 in barrel 22. Channel 48 is located in barrel 22 immediately forward of the set of segments of locking threads 26 which are uppermost when the barrel is rotated to the lock position and so as to receive the end of key 42 when the locking threads and the interrupted threads 30 are interengaged.

Key 42 is biased downwardly to press the bottom end thereof into channel 4S by measn of a spring device 50 which is disposed in barrel jacket 18 so as to have engagernent with the underside of thumb portion '38. Spring device S0 includes a cuplike housing 52 which is received by a mating hole 54 vertically disposed in barrel jacket 18 and by slot 46 in breech ring 24 so that Vthe base of the housing contacts the periphery of barrel 22 rearwardlyjof channel 48. The diameter of housing 52 is greater than the width of channel 48 to prevent insertion thereinto and thereby assume contact of the housing vwith the periphery of barrel 22. A compressible coil spring 55 is provided in housing 5,2 between the bottom thereof and a plunger 56 slidingly disposed therein for biasing the plunger upwardly. Plunger 56 is vretained in housing 52 to preload spring 55 by a snap ring 58 installed at the mouth of the housing. A lug 60 is disposed in thumb portion 38 for contact with the top end of plunger 56.`

Thus, to release barrel 22 for removal `from gun 12, thumb portion 38 is pressed downwardly to withdraw the end Vof key 42 from channel 48. Barrel 22 vis then free to be rotated for disengaging locking threads 26 from interrupted threads 38 and, upon disengagement, the barrel may be pulled forwardly from barrel jacket '18. With the withdrawal of barrel 22, spring device S0 is left unsupported'and, therefore, cannot act resiliently against lever 34.

To install barrel 22 to gun 12, the one of the recesses 28 leading the set of segments of locking threads 26 immediately rearward of channel 48 is aligned -with key 42y and thenthe barrel is pushed rearwardly into position for locking rotation. The rearward movement of barrel 22 into jacket 18 causes key 42 and housing 52 to be cammed upwardly onto the periphery of barrel '22 by the contacts of such key and housing with chamfer 23 and radial ramp 31 in the associated recess 28, whereby spring device 5t) is loaded to bias key 42 downwardly. When barrel 22 is fully inserted into barrel jacket 18, itis rotated for interengagement of locking threads 26 and interrupted threads 30. When channel 48 is moved into registry with key 42 with the rotation of barrel 22, the key is pressed into the channel by spring device50 to lock the barrel in place.,V A v Y Gun 12 is adapted to lire from open bolt position and, therefore, bolt 16 is relcasably latched adjacent the recoil position thereof by a scar 62. Sear 62 is pivotally mounted in receiver 14 adjacent the rear end thereof so as to be displaceable between a holding and a release position. Sear 62 is actuated, as hereinafter described, by a trigger 64 which is pivotally mounted on barrel jacket 18 (looking towards the front of machine gun 12 from the rear end thereof) and in the same cross-sectional portion thereof as lever 34.

Sear 62 is pivotally mounted to receiver 14 by means of a transversal shaft 66, whereby, the sear is pivoted between a holding and a release position. An arm 68 is iixedly mounted at one end on shaft 66 and a link 70 connects the free end of such arm to the rear end of a trigger bar 72 which is longitudinally disposed in receiver 14 for translational reciprocation. The front end of trigger bar 72 extends from the front end of receiver 14 and xedly assembled on such front end is a cylinder 74 which is received by a cylindrical housing 76. Cylinder 74 is fixed to housing 76 by a retainer ring 78.

A rod 80 extends longitudinally through a mating bore 82 in the front end of housing 76 so that the rear end of such rod extends into cylinder 74. A collar 84 is pinned on the rear end of rod 80 and such collar is disposed for sliding displacement in cylinder 74 so as to be contactable with the rear end thereof.

A compressible coil spring 85 is coiled around rod 80 between collar 84 and the front end of housing 76 so as to be compressible therebetween. The front end of rod 80 extends into a trigger housing 86 mounted on the right side of barrel jacket 18 adjacent lever 34, which trigger housing includes a pair of longitudinally spaced ends 87 and an arcuate cover 88 extending over the top and right side thereof. A bracket 89 is fixed on rod 80 adjacent the front end thereof and such bracket is provided with a radially extending axle 90 which rotatingly mounts an inner roller 91 and an outer roller 92. Coiled around rod 80 between bracket 89 and the rear end of trigger housing 86 is a torsional spring 94 which is connected at one end to the bracket and at the other end to the rear one of the ends 87 to bias the bracket for clockwise rotation.

Trigger 64 is of flapper configuration and includes a planar actuator portion 96 which is hingedly connected at the left side to trigger housing 86 by a pin 98 and an arcuate cam portion 100 which extends upwardly from the right side of the actuator portion concentric to such pin. Extending in the cam portion 100 from the free side thereof is a cam slot 102 which slidingly receives inner roller 91. Actuator portion 96 extends normally below cover 88 of trigger housing 86 so that the fingers of an operator, or mechanical or solenoid means, may press trigger 64 in a counterclockwise direction upwardly into the trigger housing.

Rod 80 is free to rotate and, therefore, a dog v104 is provided to hold inner roller 91 against pivotal displacement by cam slot 102 when trigger 64 is actuated, whereby cam slot 102 is movable over inner roller 91 to convert pivotal displacement of trigger 64 to translational displacement of rod 80. Dog 104 is rotatingly mounted on a shaft 106 which extends longitudinally through trigger housing 86 adjacent lever 34 and includes a pair of longitudinally spaced lugs 108 disposed on the side thereof adjacent the lever and such lugs to receive therebetween a lug 110 formed on the adjacent end of a pin 111 which extends transversely through thumb portion 38. A pin 112 extends longitudinally through lugs 108 and 110 to hinge lever 34 and dog 104 together so that pivotal displacement of either lever 34 .or the dog is transferred to the other member. A dog 104 is also provided with a longitudinal slide surface 114 disposed on the side thereof opposite lugs 108 which slide surface is disposed for contact with outer roller 92 to prevent pivotal displacement thereof when lever 34 is in the normal locking position thereof. Sliding surface 114 is displaced out of contact with outer roller 92 when lever 34 is depressed to the unlocking position thereof. A torsional spring 116 is operationally disposed between dog 104 and trigger housing 86 for biasing the dog for counterclockwise rotation, whereby sliding surface 114 is displaced `away from contact with outer roller 92 when spring device 50 is not supported by barrel 22 to act resiliently against lever 34. i

Thus, when' barrel 272 isrlockfed in position, front portion 86 of lever 34 is biased downwardly by spring device 50 to press key 42 into channel` 48 and thumb portion 38 of the lever is, consequently, pivoted upwardly. With thumb portion 38 in its uppermost position, dog.104, through the hinged connection thereof with the thumb portion, is positioned sothat sliding surface 114 is in contact with outer roller 92.

To iire gun 12, trigger 64 is actuated by pressing up- Wardly on actuator portion 96 thereof. This rotatingly displaces cam portion 100 so as to move cam slot 102 over inner roller 91. As roller 91 is prevented from pivotalA displacement because of the contact of outer roller 92 with sliding surface 114, the displacement of cam slot 102 relative to the inner roller converts pivotal displacement of trigger 64 to rearward displacement of rod 80.

The rearward displacement of rod is transferred to trigger bar 72, through the contact of collar 84 with the end of cylinder 74, and from the trigger bar to link 70. The rearward displacement of link 70 is converted to pivotal displacement of sear' 62through the connection of the link with the end of arm 68, whereby sear 62 is pivot"- ally displaced to release bolt 16.

When barrel 22 is to be replaced,vthumb portion 38 of lever 34 is pressed downwardly. This causes front portion 36 to be displaced upwardly, removing key '42 from channel 48 and rotating dog 104 to displace sliding surface 114 thereon upwardly and out of contact with outer roller 92. Thereby, Sear `62 is `made safe against accidental actuation by trigger 64 because, with sliding sur-A face 114 out of contact with outer roller 92, any pivotal displacement of the trigger would onlycause bracket `89 to rotate around the axis of ,md80 and so the displacement of the trigger would Anot lbe converted to rearward displacement of the rod.

After key 42 is disengagedfro-m channel 48, barrel20v is free to be rotated for disengaging locking threads 26 thereon from interrupted threads 30m breech ring 24. When locking threads `26 and interrupted threads 38 are disengaged, o ne of the recesses 2S is aligned with spring device 50 and key 42fso that barrel 22 may bewithdrawn forwardly from barrel jacket 18. 'I'he bias of spring device 50 against lever 34 isy relieved when the breech end of barrel 22 is withdrawn, out Vof contact with the spring device so that the pressure of torsional spring 116 is permitted to lift sliding surface 114 out of contact with outer roller 92.` l y j To install `a new barrel 22 in gun 12, the one of the recesses 28 leading the segment of thelocking threads 26 located immediately rearward of channel 48 is aligned with key 42 and then the barrel is pushed into barrel jacket'l. When barrel 22 is'moved into contact with key 42 and spring device V50the contact thereof by chamfer 25 and radial ramp 31 on the contacted recess 28 cams key 42 and housing 52 of rspring device 50 onto the periphery of the barrel to load'springSS andl bias with key'42 and, therefore, through the bias of spring device 50^the key is inserted thereinto. When key 42 is inserted into channel 48, front portion 86 of lever 34 is displaced downwardly and thumb portion 38 is, consequently, raised to pivot dog "104 hinged thereto so that sliding surface 114 is positioned for contact with outer roller 92. Torsional spring 94 holds inner -roller 91 in the mouth of cam slot 102 and clear of sliding surface 114 so that outer roller 92 will not interfere with the pivotal displacement of dog 104.

From the foregoing it is clearly apparent that if key 42 is not fully inserted into channel 4S to assure positive locking of barrel 22 :to breech ring 24, dog 104 will be displaced so that sliding surface 114 thereon is out of contact with outer roller 92. Therefore, pivotal displacement of trigger 64 cannot be transferred to sear 62. Moreover, if key 42 should become disengaged from channel 4S while machine gun 12 is being fired, the firing will be automatically stopped to prevent what would otherwise be a hazardous condition. It is also evident that if the trigger should be accidentally actuated during change of barrel 22, bolt 16 will not be released from the recoil position and, therefore, require gun 112 to be charged before it is ready to Ibe tired. It is also clear that the barrel lock safety device of this invention is simple but rugged in construction, easy to manufacture, and positive in operation.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim:

1. ln a rearm, a pivotal lever, a key connected to said lever for the transfer of movement therebetween, said key being positionable by said lever for locking a barrel in an assembled position, a pivotal Sear, a pivotal trigger, means for transferring displacement of said trigger to said Sear, and means connected to said lever for rendering said transfer means inoperative when said key is out of position for locking said barrel in the assembled position.

2. In a firearm, a pivotal lever, a key connected to said lever for transferring movement therebetween, said key being positionable by said lever for locking a replaceable barrel in an assembled position, a pivotal sear, a pivotal trigger, means for transferring displacement of said trigger to said sear, a spring device supported by the barrel when in the assembled position, and means connected to said lever and `disposed in cooperation with said spring device for rendering said transfer means inoperative when the barrel is removed from the firearm.

3. In a firearm having a receiver with a barrel jacket extending forwardly therefrom, a lever pivotally supported by the barrel jacket, a key connected to said lever for transferring movement therebetween, said key being positionable by said lever for locking a replaceable barrel in an assembled position in the barrel jacket, a sear pivotally disposed in the receiver, a trigger pivotally supported 'by the barrel extension, means for transferring displacement of said trigger to said Sear, said transfer means including a trigger bar and cam means for converting pivotal displacement of said trigger to translational displacement of said trigger bar, and means connected to said lever for rendering said cam device inoperative when said key is out of position for locking the barrel in the assembled position.

4. In a firearm having a receiver with a barrel jacket extending forwardly therefrom, a lever pivotally supported by the barrel jacket, a key connected to said lever for transferring movement therebetween, said key being positionable by said lever for locking a replaceable `barrel in an assembled position in the barrel jacket, a sear pivotally disposed in the receiver, a trigger pivotally supported by the barrel jacket, means for transferring displacement of said trigger to said Sear, said transfer means including a trigger bar and cam means for converting pivotal displacement of said trigger to translational displacement of said trigger bar, a spring device Ifor locking the `barrel in the assembled position, whereby n said sear is inoperable by said trigger when the barrelk is removed.

5. The combination as defined in claim 4 wherein said cam means includes'a cam slot provided in a camv portion of said trigger and a roller follower slidingly received by said cam slot, said roller follower being mounted on a rod connected to said trigger bar so as to be pivotal relative thereto, and wherein said means for rendering said cam means inoperative includes a dog hinged to said lever -for pivotal displacement thereby and a sliding surface disposed on said dogfor sliding contact with a roller coaxially disposed relative to said roller follower for preventing rotation thereof, whereby pivotal displacement of said trigger moves said follower along said sliding surface for ltranslational displacement of said rod.

6. In a firearm having a receiver with a barrel jacket extending forwardly therefrom and a bolt slidingly disposed in the receiver for reciprocation between a battery and a recoil position, a barrel assembly including a breech ring secured to the receiver for limited longitudinal reciprocation, a barrel and means for rotatingly engaging said barrel to said ybreech ring to prevent relative axial displacement therebetween, a manually actuated lever pivotally mounted on said barrel jacket, a key connected to said lever for transfer of movement therebetween, said key being engageable with a channel in said -barrel when engaged with said breech ring to lock said barrel against rotational displacement relative thereto, a Sear pivotally mounted in the receiver for releasably securing the bolt adjacent the recoil position thereof, a longitudinal trigger bar disposed in the receiver for axial reciprocation, lever means interposed between said trigger bar and said sear for converting axial displacement of said trigger bar to pivotal displacement of said sear, a trigger mounted on the barrel jacket for pivotal displacement, cam means for converting pivotal displacement of said trigger to longitudinal displacement of a rotatable rod connected to said trigger bar for transferring the longitudinal displacement thereto, and means connected to said lever for rendering said cam means inoperative when said key is out of position for locking said barrel against rotational displacement.

7. The combination as defined in claim 6 wherein said cam means for converting pivotal displacement of said trigger to longitudinal displacement of said rod includes a cam slot formed in a cam portion of said trigger, a bracket With a radially extending axle fixed to said rod, a first roller mounted on said axle for sliding engagement with said cam slot, and a sliding surface disposed for sliding engagement with a second roller mounted on said axle to prevent rotation of said rod so that said first roller is longitudinally displaceable by said cam slot when said cam portion is pivotally displaced.

8. The combination as defined in claim 6 wherein said cam means for converting pivotal displacement of said trigger to longitudinal displacement of said rod includes a cam slot formed in a'carn portion of said trigger, a bracket with a radially extending axle fixed to said rod,

an inner roller mounted on said axle for sliding engage-V j ment with said cam slot and a dog having a sliding surface disposed for sliding engagement with an outer roller mounted on said axle for preventing rotation of said rod, whereby said inner roller is longitudinally displaced by said cam slot when said cam portion is pivotally displaced, and wherein said means for rendering said cam means inoperative Vincludes means for pivotally mounting said dog so that said sliding surface thereon is displaceable out of contact with said inner roller, and hinge means connecting said dog to said lever so as to be pivotal thereby and so that said dog is displaced by said lever to position sai-d sliding surface out of contact with said inner roller when said key is not fully engaged with said channel.

9. The combination as defined in claim 6 and including a spring device supported by said barrel when engaged with said breech ring and disposed for contact by said lever for biasing said key into position for engaging said channel, and a spring disposed lfor activating said means for rendering said cam means inoperative when said spring device is unsupported, whereby said sear is not actuatable by said trigger when said barrel is removed from the barrel jacket.

l0. The combination as defined in claim 6 wherein said cam means for converting pivotal displacement of said trigger to longitudinal displacement of said rod includes a cam slot formed in a cam portion of said trigger, a bracket with a radially extending axle txed bo said rod, an inner roller mounted on said axle for sliding engagement with said cam slot and a dog having a sliding surface disposed thereon for engagement with an outer roller mounted on said axle to prevent rotation of said rod, whereby said inner roller is longitudinally displaceable by said cam slot when said cam portion is pivotally displaced, wherein said means for rendering said cam means inoperative includes means for pivotally mounting said dog so that said sliding surface thereon is displaceable out of contact with said inner roller and hinge means connecting said dog to said lever so as to be pivotal thereby and so that said dog is displaced by said lever to position said sliding surface out of contact with said inner roller when said key is not fully engaged with said channel, and including a spring device disposed for support by said barrel when engaged with said breech ring and for contact with said lever for biasing said lever to press said key into engagement with said channel and said sliding surface -into position for contact with said outer roller, whereby said lever is unsupported when said barrel is removed from the barrel jacket, and a spring disposed for pivoting said dog to displace said sliding surface thereon `away from contact with said outer roller when said spring device is unsupported by said barrel, whereby said sear is not actuatable by said trigger when said barrel is removed from the barrel jacket.

1l. The combination as defined in claim 10 and including cam surfaces disposed on said barrel for camming said spring device and said key onto the periphery of said barrel to load said spring device when said barrel is inserted into the barrel jacket.

No references cited. 

